Exemplary embodiments disclosed herein generally relate to electrostatographic imaging machines and, more particularly, to a method for comparing calculated sheets needed against sheets available employed in an electrostatographic imaging machine.
In a typical electrostatographic imaging machine, a photoreceptive member is charged, positively or negatively, to a substantially uniform potential so as to sensitize a photoconductive surface thereof. The charged portion of the photoconductive surface is then exposed to a light image representative of a document to be produced. Exposing the charged photoreceptive member to the light image discharges the charged portion of the photoconductive surface in areas corresponding to non-image areas in the document to be produced while maintaining the charge in image areas, thereby creating an electrostatic latent image of the document to be produced on the photoreceptive member. This latent image is subsequently developed into a visible image, corresponding to the informational areas contained within the document to be produced, by depositing oppositely charged developing material onto the photoreceptive member surface such that the developing material is attracted to the charged image areas on the photoconductive surface.
Thereafter, the developing material is transferred from the photoreceptive member to a print media or receiving sheet or to some other image support substrate, to create an image, which may be permanently affixed to the print media sheet, thereby providing an electrophotographic document. In a final step in the process, the photoconductive surface of the photoreceptive member is cleaned with a cleaning device, such as elastomeric cleaning blade, to remove any residual developing material which may be remaining on the surface thereof in preparation for successive imaging cycles.
The electrostatographic process described hereinabove for electrophotographic imaging is well known and is commonly used for light lens copying of an original document. Analogous processes also exist in other electrostatographic printing applications such as, for example, digital laser printing where a latent image is formed on the photoconductive surface via a modulated laser beam, or ionographic printing and reproduction where charge is deposited on a charge retentive surface in response to electronically generated or stored images.
Typically, the information forming the document or documents to be printed is provided to the imaging machine in electronic form or is converted to electronic form by the imaging machine from the original document (or documents). Alternatively, copying of the document can occur without digitizing an original document (i.e., analog copying), such as occurs in some light lens copying applications. The information forming the document to be printed can come from any source, such as, for example, a scanner, a software program, a storage medium, a computer, a network, etc., or some combination of these sources. The document or documents to be printed, whether computer generated or created from an original document to be copied, can be referred to as a print job. In one example, the imaging machine is an all-in-one imaging machine that enables both copying and printing. Such an all-in-one imaging machine can include an integral scanner for converting an original document into electronic form and can include suitable connections for receiving other electronic representations of documents from a source, such as a computer, portable memory device, network, facsimile machine or the like.
For providing the print media sheet, imaging machines often include one or more trays for holding a stack of blank print media sheets. As needed, one sheet of a stack of sheets, usually a top sheet, is fed through the imaging machine for receiving and having permanently affixed thereto the toner, ink or the like, as will be known and understood by those skilled in the art. Heretofore, when a stack of sheets in an imaging machine was depleted, all printing ceased, even if the imaging machine was in the middle of a print job. Thus, regardless of the number of print media sheets necessary for a particular print job, the imaging machine typically started the print job and stopped when no more blank print media sheets were available. Often, the user or customer was first informed of the need for more print media sheets in the imaging machine tray only after stoppage of the print job. This annoying and unproductive stop decreases productivity and requires the user to attend to the imaging machine before the print job can be resumed and completed.
Accordingly, there is a need to eliminate or at least lessen the likelihood of annoying and unproductive stops in print jobs of imaging machines, particularly when the stop is related to an empty print media sheet supply tray and the print job being processed requires additional print media sheets. It would be desirable to inform the user earlier, i.e., before the print job stops, that there is insufficient print media sheets in the imaging machine supply tray to complete the print job so that the user could re-supply the tray prior to the print job stoppage.